This lecture explores the fascinating world of vaginal bacteria, focusing on Lactobacillus crispatus and its role in women's health. Topics include the impact of hormones on the vaginal microbiome, the importance of maintaining a healthy pH balance, and the potential benefits of probiotic bacteria. The lecture also discusses the association between vaginal microbiota and fertility, pregnancy outcomes, and infections. Furthermore, it delves into the challenges of dysbiosis and the potential of probiotic interventions. The presentation concludes with a call to action for women to participate in citizen science initiatives to advance research on women's health.